Increased reliance on semiconductor devices has resulted in a concomitant need for increased stringency of manufacturing quality control sceening procedures. One traditional quality control test is commonly referred to as a wire pull test. To facilitate an understanding of a wire pull testing procedure, a description of the general structure of a typical semiconductor device is provided.
A typical semiconductor device includes a die which is fabricated from semiconductor material to form electronic components and interconnects thereon. The die is generally encompassed by a casing to protect the die from damage or degradation caused by external sources. Leads, also referred to as pins, protrude externally from the casing to enable connectivity between the semiconductor device and other circuitry and components external to the device. Die bonding pads are provided on the die to couple the die to the leads. Lead pads are mounted on the casing and are connected to the leads. To provide connectivity between the die and the leads, small wires are connected between the lead pads and the die bonding pads using a wire bonding process.
Semiconductor devices are generally produced in batches or lots. A typical quality control procedure involves subjecting a number of randomly selected semiconductor devices from a particular lot to a wire pull test in accordance with a given test specification. Such a specification typically outlines the number of semiconductor devices from each lot that must be tested, and the number of wires for each semiconductor device that must be subjected to the test. As an example, one specification requires the testing of a total of fifteen wires in four semiconductor devices per lot.
A typical wire pull test is designed to assess the strength of the bonds between the wire and both the die bonding pads and the lead pads to which the wires are connected. The wire pull test is performed by accessing the die, the wires, the die bonding pads, and the lead pads, and hooking a wire pulling member of the test apparatus to a selected wire of the semiconductor device. A force is applied to the wire pulling member so as to pull the wire away from the pads. In accordance with a destructive wire pull testing procedure, the pull force is increased until either the wire breaks or the bond between the wire and either the die bonding pad or the lead pad breaks. The breaking force is then determined and recorded. If the breaking force is greater than a threshold provided in the specification, the test is considered a success, otherwise, the test is considered a failure. A typical test specification provides guidelines as to the number of tests that must be successful in order for the lot to be considered acceptable.
A typical wire pull testing apparatus includes a fixture which is used, with limited success, to support the subject semiconductor device during the test. Currently, many conventional fixtures fail to satisfactorily constrain the device during the wire pull test, often requiring manual holding of the device under test. Other conventional fixtures are constructed for use with one particular device type, thus requiring the testing facility to make available a multitude of fixtures configured for use with a multitude of device types. Performing wire pull testing using existing fixtures is often inefficient in terms of testing time and cost, due to the need for a high degree of manual intervention during each test.